U.S. patent number 4,750,096 [Application Number 07/003,183] was granted by the patent office on 1988-06-07 for fluorescent light fixture.
This patent grant is currently assigned to Lumatech Corp.. Invention is credited to Kenneth Lim.
United States Patent |
4,750,096 |
Lim |
June 7, 1988 |
Fluorescent light fixture
Abstract
A fluorescent light fixture which employs a lamp fitting,
electrical ballast, and a base which are inter linked, to
mechanically and electrically, to connect to a fluorescent lamp to
an electrical socket. A heat conductive housing and a spacer
mechanism transport heat from the ballast to the exterior of the
lighting fixture when the same is in operation.
Inventors: |
Lim; Kenneth (Piedmont,
CA) |
Assignee: |
Lumatech Corp. (Oakland,
CA)
|
Family
ID: |
21704591 |
Appl.
No.: |
07/003,183 |
Filed: |
January 13, 1987 |
Current U.S.
Class: |
362/218; 362/260;
362/294 |
Current CPC
Class: |
F21V
19/0095 (20130101); F21V 23/02 (20130101); F21V
29/004 (20130101); H01J 61/325 (20130101); F21V
29/505 (20150115); F21V 29/773 (20150115); F21V
29/74 (20150115); F21V 29/75 (20150115); F21Y
2103/37 (20160801) |
Current International
Class: |
F21V
29/00 (20060101); F21V 23/02 (20060101); F21V
19/00 (20060101); H01J 61/32 (20060101); F21S
002/00 () |
Field of
Search: |
;362/218,294,260,222,264,310,373 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Myhre; Charles J.
Assistant Examiner: Okonsky; David A.
Attorney, Agent or Firm: Bielen & Peterson
Claims
What is claimed is:
1. A fluorescent light fixture for mounting a fluorescent lamp to
an electrical light socket to be employed for illumination of an
object comprising:
a. a fitting for mechanically holding the lamp, said fitting being
electrically linked to the lamp;
b. an electrical ballast, said ballast being positioned relative to
said fitting and being electrically linked to said fitting;
c. a base, said base being positioned adjacent said ballast, said
base including means for mechanically and electrically connecting
said base to the electrical light socket;
d. a heat conductive housing enclosing said fitting and ballast,
said housing having an interior surface and an exterior
surface;
e. means for conducting heat generated by said ballast therefrom
and to the interior surface of said housing, said heat transporting
means including at least one heat conductive spacer interposed and
contacting said ballast and said interior surface of said
housing.
2. The fluorescent light fixture of claim 1 in which said exterior
surface of said housing includes at least one fin for dissipating
heat conducted to said outer surface of said housing from said
ballast.
3. The fluorescent light fixture of claim 1 in which said housing
interior surface of said housing includes a rounded portion, said
ballast includes a flat surface, and said spacer includes a rounded
surface and a flat surface, said spacer rounded and flat surfaces
contacting said rounded portion of said housing interior surface
and said flat surface of said ballast, respectively.
4. The fluorescent light fixture of claim 1 which further comprises
a reflector positioned a sufficient distance from the fluorescent
lamp to reflect light therefrom.
5. The fluorescent light fixture of claim 4 which further includes
a lens placed over said reflector.
6. The fluorescent light fixtures of claim 5 which further includes
a lower placed adjacent said lens for selectively blocking light
originating from the fluorescent lamp.
7. The fluorescent light fixture of claim 6 in which said exterior
surface of said housing includes at least one fin for dissipating
heat conducted to said outer surface of said housing from said
ballast.
8. The fluorescent light fixture of claim 7 in which said housing
interior surface of said housing includes a rounded portion said
ballast includes a flat surface, and said spacer includes a rounded
surface and a flat surface, said spacer rounded and flat surfaces
contacting said rounded portion of said housing interior surface
and said flat surface of said ballast, respectively.
9. The fluorescent light fixture of claim 4 in which said reflector
is of a curved sectional configuration determined by establishing a
circular configuration of the light source of the fluorescent lamp
establishing a representative first circular image of identical
diameter to said circular source, representation, said first
circular image being displaced from said circular source
representation and away from the object being illuminated;
determining a first point as the intersection of a first line
tangent to said circular source configuration and said first
circular image; determining a second point as the intersection of a
first arc of a circle of the diameter of said circular image and
employing said first point as the center and a first pair of lens
of equal length intersecting said first arc of a circle one of said
first pair of lines emanating from the center of said first
circular image and the other of said first pair of lines emanating
from the center of said circular source representation; determining
a third point as the intersection of a second arc of circle of the
diameter of said first circular image and employing said second
point as the center, and a second pair of lines of equal length
intersecting said second arc of a circle, one of said second pair
of lines emanating from the center of said circular source
representation and the other of said second pair of lines emanating
from the center of a second circular, image of identical diameter
to said circular source representation, and connecting said first
second and third points with a smooth continuous curve.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a novel fluorescent light fixture
which may be screwed into a conventional light socket in
substitution for an incandescent light bulb.
Standard incandescent light bulbs are typically rated between 40
watts and 150 watts. Each incandescent bulb includes an "Edison"
base which screws into a conventional light bulb socket. The
standard incandescent lamp lasts about 1000 hours. It has long been
realized that fluorescent lighting consumes far less electricity to
produce lighting levels which are equivalent to incandescent bulbs.
In the past, fluorescent lighting has been restricted to custom
fluorescent fixtures which are typically 2 feet by 4 feet and
employ bulbs approximately 4 feet in length. These fluorescent
lighting fixtures must be specially installed and are, thus,
incompatible with the standard screw-in light socket employed by
standard incandescent light bulbs.
A recent development in fluorescent lighting has resulted in the
production of a PL fluorescent lamp. In general, the PL lamp is a
U-shaped lamp having a starter built into the base portion thereof.
Generally, the PL fluorescent lamp is measured in wattages ranging
from 4 watts to 13 watts, which generally correspond to the 40-150
watt level of the standard incandescent light bulb. Also, the PL
fluorescent lamp has a lamp life of about 10,000 hours compared to
the 1000 hours of the standard incandescent light bulb, previously
noted.
Early fluorescent light fixtures such as model 2000, 3000-9 and
3013 manufactured under the trademark Refluor and the
Reflect-A-Star manufactured by Lumatech Corporation of Oakland,
Calif. employed in PL lamp in a body having an external, plug-in
ballast. In some cases a replaceable starter was also provided.
Although the PL lamp did perform satisfactorily in producing
required lighting levels, the plug-in components prevented the
lamps in being used in certain lighting fixtures such as down
lights, recessed lights and the like.
A fluorescent light fixture which employs a fluorescent lamp, has a
slim configuration, and is capable of dissipating heat generated by
an internally located ballast would be great advance in the field
of lighting.
SUMMARY OF THE INVENTION
In accordance with the present invention a novel and useful
fluorescent light fixture which overcomes many of the disadvantages
in the prior art is herein provided.
The fluorescent light fixture, or unit, of the present invention
utilizes a fitting for mechanically holding the lamp. The lamp,
which is a standard PL type florescent lamp, is also electrically
linked to the same. An electrical ballast is positioned relative to
the fitting and is, likewise, electrically linked to the same.
Thus, the electrical ballast controls the fluorescent lamp being
used. A base member is positioned adjacent the ballast and includes
means for mechanically and electrically connecting the ballast to a
standard electrical, screw-in, light socket.
A housing is also provided in the present fixture which is heat
conductive and possesses interior and exterior surfaces. Means is
included for transporting heat generated by the ballast to the
interior surface of the housing. The heat transportation means may
take the form of at least one heat conductive spacer interposed and
contacting the ballast and the interior surface of the housing. If
the housing interior surface is rounded, the spacer would include a
rounded surface which is intended to contact the rounded interior
surface of the housing. In addition, the spacer may be constructed
with a flat surface to contact a flat surface of the ballast. Thus,
heat may be transported from the ballast to the spacer and finally
to the heat conductive housing for dissipation to the ambient
environment. In this regard, the housing exterior surface may
include one or more fins to aid in the dissipation of the heat
conducted thereto.
The light fixture of the present application also includes a
reflector to direct light originating from the fluorescent lamp to
the area being lighted. The reflector includes a specular surface
of curved configuration, shaped generally in the form of a "drip"
curve. The sectional configuration of such a reflector is
determined by projecting a first circular image of the fluorescent
lamp laterally and behind the theoretical specular reflecting
surface i.e. opposite to the direction of the object being
illuminated. A first point is determined by an arc having a radius
of a diameter of the first circular image and a pair of lines
equidistant between the source and a first circular image. A series
of circular images of equal diameter to the first circular image
are then extended along a line perpendicular to the axis of the
lamp, with each one determining the subsequent point in the
specular reflecting surface. A continuous smooth curve is then
drawn through the multiplicity of points so determined, which
represents the curvature of the specular surface of the
reflector.
It may be apparent that a novel and useful fluorescent fixture has
been hereabove described.
It is therefore an object of the present invention to provide a
fluorescent light fixture which is of a slim configuration and is
adaptable to being fitted within a standard screw-in incandescent
light socket.
It is another object of the invention to provide a fluorescent
light fixture which efficiently dissipates heat generated by an
internally located fluorescent ballast.
Another object of the present invention is to provide a fluorescent
light fixture which possesses a reflector which maximizes lighting
levels along the optical access thereof and immediately adjacent to
the same.
Another object of the present invention is to provide a fluorescent
light fixture which may be used in indoor or outdoor
environments.
The invention possesses other objects and advantages especially as
concerns particular characteristics and features thereof which will
become apparent as the specification continues.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the fluorescent light fixture
having a portion cut away.
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.
FIG. 3 is a sectional view taken along line 3--3 of FIG. 1.
FIG. 4 is a sectional view taken along line 4--4 of FIG. 1.
FIG. 5 is a top plan view of the fluorescent light fixture having
the lens portion removed.
FIG. 6 is a schematic view representing the sectional configuration
of the reflector of the fluorescent light fixture of the present
invention.
For a better understanding of the invention reference is made to
the following detailed description of the preferred embodiments
thereof which should be referenced to the hereinabove described
drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various aspects of the present invention will evolve from the
following detailed description of the preferred embodiments which
should be referenced to the hereinabove drawings.
The invention as a whole is shown in the drawings by reference
character 10. The fluorescent lighting fixture or unit 10 includes
as one of its element a housing 12 which is constructed of heat
conductive material such as aluminum, steel, and the like. Housing
12 is generally in the shape of a truncated cone and includes a
plurality of fins 14 spaced circumferentially, FIGS. 1 and 4. Fins
14 aid in the dissipation of heat from the interior of housing 12
which will be described hereinafter.
Unit 10 is intended to employ a standard PL lamp such as a twin
lamp manufactured by Sylvania of Danvers, Mass. PL lamps are
generally rated by wattages, varying from 5 to 14 watts, in most
cases. The lamp 16, depicted in the drawings is a 5 watt PL lamp,
although the invention is not deemed to be limited to the
employment of a PL lamp of this wattage. Lamp 16 includes a
u-shaped envelope 18 and a support 20. Light emanates from glass
envelope 18 while support 20 provides the mechanical and electrical
connection of lamp 16 to fitting 22. Prongs 24 and 26 of lamp 16
engage electrical contacts 28 and 30 with fitting 22, respectively.
Wires 32 and 34 connect to contacts 28 and 30, respectively, and
lead to ballast 36 within housing 12. Plug 38 of lamp 16
mechanically holds lamp 16 to fitting 22. Fitting 22 is itself
fixed to housing 12 by screws 40 and 42.
Ballast 36 is a standard iron core ballast normally employed with
PL lamp 16. Housing 22 includes the provision of a pair of spacers
44 and 46 which are integrally formed within the truncated conical
portion of housing 12. It should be noted that spacers 44 and 46
may be separately formed, but position in intimate contact with the
truncated conical portion of housing 12. Screws 40 and 42
threadingly engage spacers 44 and 46, respectively. Spacers 44 and
46 include flattened portions 48 and 50 and rounded portions 52 and
54, respectively. Flattened portion 48 and 50 contact the sides 56
and 58 of ballast 36. Rounded portions 52 and 54 of spacers 44 and
46 are in heat conductive relationship with the truncated section
of housing 12, since they are integrally formed therewith. Spacers
44 and 46 are constructed of heat conductive material. Thus, any
heat generated by ballast 36 is easily transferred by conduction to
the interior surface of housing 12, through housing 12, and to the
exterior surface of housing 12. Plurality of fins 14 aid in the
dissipation of heat to the ambient environment which is normally
air.
Ballast 36 is thus sandwiched between fitting 22 and bottom 64 of
housing 12. Electrical linkage from ballast 36 extends to "Edison"
base 66 which screws into a standard light socket commonly used by
incandescent light bulbs.
Reflector 68 press fits into the upper portion of housing 12 by the
use of a collar 70. The exterior of reflector 68 includes a
plurality of fins 72 which may be aligned with a plurality of fins
14 on the exterior surface 62 of housing 12. However, plurality of
fins 72 do not necessarily dissipate heat. In fact, in the
embodiment shown in FIGS. 1-6, reflector 68 and fins 72 are
constructed of plastic material and, thus, possesses an insulative
quality. Lens 74 of transparent material press fits into the outer
portion of reflector 68. Lens 74 is readily removable from
reflector 68. Louver or baffle 76 may be employed to prevent the
lateral distribution of light from unit 10 i.e. a glare cutoff
mechanism.
Turning to FIGS. 2 and 3 it may be seen that o-rings or gaskets 76
and 78 may be placed between lens 74 and reflector 68 and housing
12, respectively. Gaskets 76 and 78 render unit 10 as a rainproof
or waterproof fixture, suitable for outdoor usage.
Reflector 68 is shown in greater detail on FIGS. 5 and 6. Lamp 16
possesses tubes 80 and 82 which extend downwardly from upper
connecting portion 84. Although the shape of PL lamp 16 is
different than a incandescent bulb, a representation of the source
of light emanating from lamp 16 may take the form of a circle 86
depicted in FIG. 6. Reflector 68 includes a specular surface 88
which possesses a concave shape close to a "drip" shaped curve, in
section. That is, the curve formed by a string of uniform density
fastened at both ends and pulled downwardly in the center only by
the force of gravity. With reference to FIG. 6 it may be seen that
lamp envelope 18 is shown on end, schematically, and rotated 90
degrees, in phantom. Also, reflector 68 and specular surface 88 are
shown schematically in section.
The curvature of reflector 68 has been determined by producing an
image 90 of circular configuration and having the same diameter as
source representation 86. The center of image 90 is displaced
laterally from optical axis 92 a distance equal to its diameter. In
other words, a line 94 tangent to image 90 and source
representation 86 would also be parallel to optical axis 92. Image
90 is also displaced vertically to lie tangent to the theoretical
revolution 18A of envelope 18 about axis 92, depicted in phantom in
FIGS. 6. First virtual image 96 is oriented relative to source
representation 86 along line 94 and in a direction opposite to the
intended direction of light being projected from reflector 68. A
first point 98 is determined as the intersection of line 94 and
line 100 connecting the centers of first circular, virtual image 96
and source representation 86. A second point 102 is determined as
being the arc of a circle equal to the diameter of source
representation 86 and employing point 98 as the center of the arc
of the circle. Arc 104 is intersected by lines 106 and 108, which
are of equal length and emanate from the centers of virtual image
96 and source representation 86. A third point 110 is determined as
a arc of a circle of diameter of source representation 86 using
point 102 as the center of the circle of such an arc 112. A second
virtual image 114 is displaced laterally relative to lamp 16 and
along a line 116 which is essentially parallel to a plane
perpendicular to optical axis 92. Lines 118 and 120 of equal length
connect the center of source representation 86 and second virtual
image 114 and intersect arc 112. Points 122 and 124 are similarly
obtained forming images 126 and 128 in conjunction with source
representation 86. A smooth curve 130 is used to connect points 98,
102, 110, 122, and 124. Curve 130 represents the curvature of
specular surface 88 of reflector 68, in section. It has been found
that specular surface 88 delivers a highly concentrated light
projection directly above the unit fixture 10 at a small radius
about a point formed where axis 92 intersects the surface to be
lighted. Specular surface 88 is particularly useful for recessed
downlights.
In operation, unit 12 is screwed into a standard incandescent light
socket employing "Edison" base 66. Light from lamp 16 will be
projected downwardly or outwardly, as the case may be, by the use
of reflector 68 in a "flood" configuration. Any heat generated by
ballast 36 will be transferred to the exterior surface 62 of
housing 12 by the use of spacers 44 and 46. Unit or fixture 10
generally possess a life which is 10 times longer than a comparable
incandescent bulb. Unit 12 is depicted as using 5 watt fluorescent
PL lamp and has been determined to satisfactorily replace a 40 watt
incandescent bulb. Also, reflector 68 efficiently projects light
from lamp 16 to the extent that a five watt fluorescent PL lamp may
be substituted for a 7 watt PL lamp without reflector 68. It has
also been determined that the operating cost of unit 10 is one
seventh that of an incandescent bulb, and delivers equivalent
lighting levels. Moreover, there is a great savings in labor cost
expended in the replacement of burned out lamps.
While in the foregoing embodiments of the present invention have
been set forth in considerable detail for the purposes of making a
complete disclosure of the invention, it may be apparent to those
of skill in the art that numerous changes may be made in such
detail without departing from the spirit and principles of the
invention.
* * * * *